Dear Mandeep,

you can create a mapped mesh on a surface by adding "Mapped FAce Meshing" to the corresponding face. This would lead to an arbitrary mesh within the volume but a mapped mesh on the surface.

IT should be better if you use the method "sweep" or "multizone" (if the volume can be sweeped, multizone performes a sweep operation). This will lead to a mapped mesh on the surface. You can specify the element size by applying "Sizing" on the surface or on the lines.

Good luck

Marco